1. Technical Field
The present invention relates to liquid ejection methods and liquid ejection apparatuses.
2. Related Art
An inkjet printer is known as a liquid ejection apparatus that ejects ink in the form of liquid onto a medium to perform printing. With regard to ink, this inkjet printer ejects various colors of ink, cyan (C), magenta (X), yellow (Y) or black (K) for example, from nozzles onto a medium to perform printing. Nozzles that eject such inks are provided in a moving member called a “carriage” that moves relative to a medium. When printing is performed, the carriage moves relative to a medium and ink is ejected from nozzles onto the medium. In this manner, printing is performed onto the entire medium.
Incidentally, such an inkjet printer has a problem that when ink is ejected onto a medium from nozzles that are moving relative to the medium, the landing position of ink ejected from the nozzles is displaced along the nozzle movement direction. In such a case, there may be an adverse effect on the printed image quality. In particular, when printing is performed by ejecting ink while moving nozzles back and forth relative to a medium, the landing positions of ink in the forward pass and the return pass are displaced from each other, which may give a significant impact on the printed image quality.
Under such circumstances, conventionally, a technique of changing the timing of ink ejection from nozzles has been employed in order to adjust the landing position of ink (see JP-A-2000-318145). Through this method, the landing position of ink can be adjusted by changing the timing of ink ejection from nozzles. As a result, it is possible to prevent deterioration in the printed image quality.
However, it has been difficult in some cases to sufficiently prevent deterioration in the printed image quality in the upstream-side end portion or the downstream-side end portion of the transported medium. This is because end portions of a medium cease to be secured by a transport section such as a transport roller or the like that transports the medium in order to perform printing on the end portions of the medium. When the end portions of the medium cease to be secured by the transport section such as a transport roller, the end portion of the medium becomes warped and is transported to a printing section in that condition. Consequently, there are cases in which a gap between a printing surface of the medium and nozzles vary, which results in displacement of the ink landing position. This sometimes results in deterioration in the image quality in the upstream-side end portion or the downstream-side end portion with respect to the transport direction of the medium. In particular, recently, efforts have been made to achieve a drastic increase in the carriage movement speed in order to increase the processing speed. Therefore, deterioration in the image quality due to variation in the gap between the printing surface of the medium and the nozzles has become an issue that cannot be neglected.